不同锌源及水平对生长育肥猪生长性能、血清抗氧化指标及微量元素利用的影响

摘要

This experiment aimed to evaluate the effects of low levels of zinc methionine (Zn-Met) or zinc sulfate (ZnSO4) on growth performance,serum antioxidant indices and utilization of trace elements to determine the appropriate level of zinc in diets for growing-finishing pigs,so that realize the high efficient utilization of resources,and reduce the environmental impact of zinc in ex.creta.Thirty-two growing-finishing pigs (Duroc× Landrace×Largewhite) with average weight of (33.70±2.76) kg were randomly divided into 4 groups with 8 replicates (1 pig per replicate).The control group was fed a basal diet,while experimental groups were fed the basal diets supplemented with 40 mg/kg Zn-Met,40 mg/kg ZnSO4 and 80 mg/kg ZnSO4 (calculate by zinc),respectively.There was a 72-day experimental period including 2 stages of a growing period and a finishing period after 7-day adaptation.The results showed as follows:1) compared with the control group,there were no significant differences on average daily gain weight,average daily feed intake and feed to gain ratio of growing-finishing pigs with different zinc sources and levels (P＞0.05).2) Compared with the control group,dietary zinc sources and levels could significantly increase the activity of total superoxide dismutase (T-SOD),glutathion peroxidase (GSH-Px) and copper and zinc superoxide dismutase (CuZn-SOD) (P＜0.05),whereas could remarkably decrease the malondialdehyde (MDA) content (P＜0.05) in serum of growing-finishing pigs.Besides,group with 40 mg/kg Zn-Met got the highest activity of T-SOD and GSH-Px and the lowest MDA content in serum,while the serum CuZn-SOD activity was increased with the addition of ZnSO4,which was the highest in 80 mg/kg ZnSO4 group.3) Compared with the control group,dietary Zn-Met significantly increased the apparent absorptivity of zine,copper and manganese (P＜0.05),while dietary ZnSO4 only significantly increased the apparent absorptivity of zinc (P＜0.05) which was decreased with the ZnSO4 addition.Meanwhile,the apparent absorptivity of zinc in the 40 mg/kg Zn-Met group was the highest.It is concluded that both zinc sources and levels can't significantly promote the growth performance,but can significantly improve the serum antioxidant indices and apparent absorptivity of trace elements of growing-finishing pigs.Under this experimental conditions,the suitable ZnSO4 supplementation level for growing-finishing pigs should be below 80 mg/kg,while 40 mg/kg Zn-Met gets a better effect.%本试验旨在研究饲粮添加低水平蛋氨酸锌(Zn-Met)或硫酸锌(ZnSO4)对生长育肥猪生长性能、血清抗氧化指标和微量元素利用的影响,确定生长育肥猪饲粮中锌的适宜添加量,实现有效利用资源,减少排泄物中锌对环境的影响.选用体重为(33.70±2.76) kg的“杜×长×大”生长育肥猪32头,随机分成4组,每组8个重复,每个重复1头猪.对照组饲喂基础饲粮,试验组在基础饲粮中分别添加40 mg/kg Zn-Met、40 mg/kg ZnSO4和80 mg/kg ZnSO4(以锌元素计).预试期7d,正试期72 d,分生长期和育肥期2个阶段.结果表明:1)与对照组相比,饲粮添加不同来源和水平锌对生长育肥猪平均日增重、平均日采食量和料重比均无显著影响(P＞0.05).2)与对照组相比,饲粮添加不同来源和水平锌能显著提高生长育肥猪血清总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)及铜锌超氧化物歧化酶(CuZn-SOD)活性(P＜0.05),显著降低血清丙二醛(MDA)含量(P＜0.05);40 mg/kg Zn-Met组血清T-SOD和GSH-Px活性最高,血清MDA含量最低;而血清CuZn-SOD活性随ZnSO4添加量的增加而升高,以80 mg/kg ZnSO4组最高.3)与对照组相比,饲粮添加Zn-Met显著提高锌、铜和锰表观吸收率(P＜0.05),而饲粮添加ZnSO4只显著提高锌表观吸收率(P＜0.05),且随ZnSO4添加量的增加而降低;40 mg/kg Zn-Met组锌表观吸收率最高.综上所述,饲粮添加Zn-Met或ZnSO4没有显著改善生长育肥猪的生长性能,但显著改善了生长育肥猪的血清抗氧化指标和微量元素的表观吸收率;本试验条件下,生长育肥猪饲粮中ZnSO4的添加量需低于80 mg/kg,而40 mg/kgZn-Met较为适宜.